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From:   tedd.an@linux.intel.com
To:     linux-bluetooth@vger.kernel.org
Cc:     Tedd Ho-Jeong An <tedd.an@intel.com>
Subject: [PATCH V2 2/2] midi: Fix random empty timestamp_high value
Date:   Fri, 19 Jun 2020 11:34:56 -0700
Message-Id: <20200619183456.38696-2-tedd.an@linux.intel.com>
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From: Tedd Ho-Jeong An <tedd.an@intel.com>

The timestamp_high value is assigned from the monotonic time but there
is a chance that the value becomes zero because it reads the value
between bit8 and bit13.

This patch makes sure the timestamp_high value get a non-zero value.
---
 profiles/midi/libmidi.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/profiles/midi/libmidi.c b/profiles/midi/libmidi.c
index 7d57e7335..cb2787db1 100644
--- a/profiles/midi/libmidi.c
+++ b/profiles/midi/libmidi.c
@@ -77,8 +77,13 @@ inline static void append_timestamp_high_maybe(struct midi_write_parser *parser)
 	if (midi_write_has_data(parser))
 		return;
 
-	parser->rtime = g_get_monotonic_time() / 1000; /* convert µs to ms */
-	timestamp_high |= (parser->rtime & 0x1F80) >> 7;
+	/* Make sure timesampt_high is assigned a non-zero value */
+	do {
+		/* convert µs to ms */
+		parser->rtime = g_get_monotonic_time() / 1000;
+		timestamp_high |= (parser->rtime & 0x1F80) >> 7;
+	} while (timestamp_high == 0x80);
+
 	/* set timestampHigh */
 	buffer_append_byte(&parser->midi_stream, timestamp_high);
 }
-- 
2.25.4